switch to typed-builder

[EdJoPaTo]

I tested this in one repo and it worked fine. As this touches basically everything it should be checked more carefully I guess.

closes #46

BREAKING CHANGES:

• FooBarBuilder::default() → FooBar::builder()
• build().unwrap() → build()

[ayrat555]

@EdJoPaTo wow. nice work. I'll test it tomorrow first thing in the morning.

but looks good!